Ch 11 Flashcards
(30 cards)
quorum sensing
allows bacterial populations to coordinate behavior so they can carry out activities that are only productive when performed by a given amount of cells in synchrony
growth factors
consist of compounds that stimulate nearby target cells to grow and divide
cell-cell recognition
two cells in an animal may communicate by interaction between molecules protruding from their surfaces
signal transduction pathway
single step but more often requires a sequence of changes in a series of different molecules
g protein coupled receptor
a cell surface transmembrane receptor that worked with the help of a g protein that bind the energ rich molecule of GTP
in g protein receptors how do they bind for signaling
specific hoops between the helices form binding sites for signaling and g protein molecules
how do g protein receptors function
embryonic development and sensory reception (5 senses)
changes in the enzyme and g protein
hydrolyzes it’s bound GTP to GDP and now inactive
RTKs
plasma membrane receptors characterized by having enzymatic activity
which part of the RTKs in in the cytoplasms
the tyrosine kinase
what’s the key difference between RTKs and g proteins
the ability of a single ligand binding event to trigger so many pathways
what are abnormal RTKs associated with
many kinds of cancer and function even in the absence of signaling molecules
dimerization
the binding of a signaling molecule causes two receptor monomers to associate closely with each other forming a complex called a dimer
ligand fates ion channel
membrane receptor containing a region that can act as a gate which the receptor changes shape
what ion is the gate blocking
Na+ and Ca2+
where are ligand ion channels most important
nervous system
what do patients w cancer have a high abundance of
breast cancer patients have high levels of receptor tyrosine kinase called HER2
protein kinase
an enzyme that transfers phosphate groups from ATP to a protein
protein phosphatases
enzymes that can rapidly remove phosphate groups from proteins, dephosphorylation
what does dephosphorylation do
inactivation protein kinases phosphates provide a mechanism for turning off the signal transduction pathway when the initial signal is no longer present
second messengers
small nonprotein water soluble molecules or ions
adenylyl cyclase
coverts ATP to cAMP in response to an extracellular signal
the pathways leading to calcium release involve what other second messengers
IP3 and DAG
the final step in signaling pathway
begins with epinephrine binding activates the enzyme that catalyzes the breakdown of glycogen
